import sys
from PyQt5 import QtWidgets, QtCore, QtGui
from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Frame(object):
    def setupUi(self, Frame):
        Frame.setObjectName("Frame")
        Frame.resize(723, 530)
        self.comboBox = QtWidgets.QComboBox(Frame)
        self.comboBox.setGeometry(QtCore.QRect(220, 170, 99, 29))
        self.comboBox.setEditable(False)
        self.comboBox.setObjectName("comboBox")
        self.comboBox.addItem("")
        self.comboBox.addItem("")
        self.comboBox.addItem("")

        self.retranslateUi(Frame)
        self.comboBox.setCurrentIndex(-1)
        QtCore.QMetaObject.connectSlotsByName(Frame)

    def retranslateUi(self, Frame):
        _translate = QtCore.QCoreApplication.translate
        Frame.setWindowTitle(_translate("Frame", "Frame"))
        self.comboBox.setPlaceholderText(_translate("Frame", "请选择"))
        self.comboBox.setItemText(0, _translate("Frame", "a选项"))
        self.comboBox.setItemText(1, _translate("Frame", "b选项"))
        self.comboBox.setItemText(2, _translate("Frame", "c选项"))


class MainFrame(QtWidgets.QMainWindow): 

   def __init__(self, parent=None):
      super().__init__(parent)
      self.ui = Ui_Frame()
      self.ui.setupUi(self)


def main():
    app = QtWidgets.QApplication(sys.argv)
    mainform = MainFrame()
    mainform.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()
